HTTrack is an open source web crawler and offline browser. It downloads desired sites and their linked sites to the local computer, thus making them available even offline. Some parts of websites might not be downloaded by default due to the robots exclusion protocol, unless disabled during the program.

HTTrack can also update an existing mirrored site and resume interrupted downloads. It is fully configurable by options and by filters (include/exclude), and has an integrated help system. There is a basic command line version and two GUI versions (WinHTTrack and WebHTTrack); the former can be part of scripts and cron jobs.